Commit 419e91ea authored by Wayne Lin's avatar Wayne Lin Committed by Lyude Paul
Browse files

drm/dp_mst: Revise broadcast msg lct & lcr 



[Why & How]
According to DP spec, broadcast message LCT equals to 1 and LCR equals
to 6. Current implementation is incorrect. Fix it.
In addition, revise a bit the hdr->rad handling to include broadcast
case.

Signed-off-by: default avatarWayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Signed-off-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210224101521.6713-2-Wayne.Lin@amd.com
parent 66922f85

drivers/gpu/drm/drm_dp_mst_topology.c

+9 −4
Original line number Diff line number Diff line
@@ -2827,10 +2827,15 @@ static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr, 
	else

		hdr->broadcast = 0;

	hdr->path_msg = txmsg->path_msg;

	if (hdr->broadcast) {

		hdr->lct = 1;

		hdr->lcr = 6;

	} else {

		hdr->lct = mstb->lct;

		hdr->lcr = mstb->lct - 1;

	if (mstb->lct > 1)

		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);

	}



	memcpy(hdr->rad, mstb->rad, hdr->lct / 2);



	return 0;

}